AAAAI: Severe Allergic Anaphylaxis Often Goes Untreated

Action Points

Explain to interested patients that severe allergic reactions and anaphylaxis may be far more common than previously understood, and that patients with severe sensitivity reactions to food or insect stings need immediate medical attention.

Explain to patients that epinephrine is under-prescribed for patients with severe allergic reactions or anaphylactic reactions to common substances such as peanuts, milk, wheat, soy, and tree nuts.

These studies were published as abstracts and presented orally at a conference. The data and conclusions should be considered to be preliminary as they have not yet been reviewed and published in a peer-reviewed publication.

MIAMI BEACH, March 6 - Life-threatening anaphylactic reactions to foods are under-diagnosed and under-treated, both in the community and in the emergency room, according to researchers here.

So found two studies -- from Massachusetts General Hospital in Boston and the Albany (N.Y.) Medical College -- that were reported at the American Academy of Allergy, Asthma, and Immunology meeting here.

"Anaphylaxis has for decades been considered a rare disease, even by physicians, even by other health care professionals," said F. Estelle R. Simons, M.D., of the University of Manitoba in Winnipeg, who is president of the American Academy of Allergy, Asthma and Immunology.

But in fact, the rate of anaphylaxis -- not just anaphylactic shock, but any type of acute, severe allergic reaction -- is likely much higher than published estimates, said Dr. Simons, because many episodes of anaphylaxis occur outside the emergency room.

"They experience anaphylaxis at home, at school, at camp, or on a plane or a bus or wherever they may happen to be," she said.

A consensus panel of the National Institute of Allergy and Infectious Diseases defined anaphylaxis as "acute onset of illness (within minutes to several hours) with involvement of the skin, mucosal tissue or both," following exposure to an allergenic substance, combined with one or more of the following: respiratory compromise, reduced blood pressure or associated symptoms of end-organ dysfunction, involvement of skin or mucosal tissues such as hives, and persistent gastrointestinal symptoms."

But even when anaphylaxis is recognized correctly in the emergency room, only about half of the patients receive epinephrine to treat it, although about a quarter of all such patients have symptoms serious enough to require hospitalization, reported researchers at Massachusetts General Hospital and Harvard Medical School.

They included all cases with a diagnosis of acute allergic reaction, including anaphylaxis, as identified by diagnostic codes for angioneurotic edema, unspecified adverse effect of drug, medicinal or biological substances when properly administered, unspecified allergy, and anaphylactic shock, food allergy, and other anaphylactic shocks.

They found that acute allergic reactions account for more than one million emergency department visits each year, but only about 1% were recorded as anaphylaxis.

But that 1% "is very different from our experience, where we found that 30% to 50% of acute allergic reactions in the emergency room are anaphylaxis," said Dr. Camargo.

Over the study period, patients with acute allergic reactions were increasingly likely to be given corticosteroids and histamine-2 blockers, but not epinephrine, the gold standard for anaphylaxis, the researchers found.

Even among those with recognized anaphylaxis, only 53% received epinephrine.

"This is quite disturbing, because we know that these are really the sickest people, and the diagnosis of anaphylaxis should be much higher," Dr. Camargo said.

In a separate study, Elinor Simons, M.D., of Albany (N.Y.) Medical College and colleagues found that among families in which one or more children have severe food allergies, 81% did not receive pre-hospital epinephrine and 34% did not receive medical care for a severe reaction.

Dr. Simons and colleagues at the Mount Sinai School of Medicine in New York surveyed families at a meeting of the Food Allergy & Anaphylaxis Network. Among 507 children with the severe food allergies, 59% were between the ages of four and 18, and 37% were younger than four.

Initial allergic reactions included symptoms such as throat tightness in 14%, lower respiratory tract symptoms in 33%, and cardiovascular symptoms in 6%. Yet of the 38% of the children who had one or more of these severe symptoms, only 6% were given epinephrine before reaching the emergency room.

The children most likely to get home-injections of epinephrine were those with symptoms of throat tightness (P<0.001) or lower respiratory symptoms (P=0.009), but not cardiovascular symptoms (P=0.24). Only about one-third of all food-allergic people sought medical attention, although 57% of those with severe symptoms did so.

Among all food allergic individuals and their families, the reasons why they didn't get medical attention included that the reaction was not severe enough (45%), the reaction was not recognized (33%), or a doctor told them it wasn't necessary (19%).

The investigators have also found that among those who sought medical attention for severe symptoms, 52% received epinephrine.

Dr. Simons noted that waiting too long could be fatal for some patients. Anaphylactic reactions to food can occur within a half hour, and reactions to stinging insects can occur in minutes, she said.

The AAAAI has launched a public information campaign to teach families, schools, physicians and other caregivers about anaphylaxis and how to handle it. The group has a resource kit that physicians can use to teach patients, and includes informational brochures, wallet cards for identifying anaphylaxis, allergy stickers, a medic alert brochure, and epinephrine self-injection training materials.

Reviewed by Robert Jasmer, MD Assistant Professor of Medicine, University of California, San Francisco

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